ant-design-vue/components/_util/hooks/useState.ts

import type { Ref } from 'vue';
import { ref } from 'vue';

export default function useState<T, R = Ref<T>>(
  defaultStateValue?: T | (() => T),
): [R, (val: T) => void] {
  const initValue: T =
    typeof defaultStateValue === 'function' ? (defaultStateValue as any)() : defaultStateValue;

  const innerValue = ref(initValue) as Ref<T>;

  function triggerChange(newValue: T) {
    innerValue.value = newValue;
  }

  return [innerValue as unknown as R, triggerChange];
}